The report from the department’s Office of Inspector General came amid mounting pressure on Trump Cabinet officials over their ethics and spending habits while in office.
“We determined that Zinke’s use of chartered flights in fiscal year (FY) 2017 generally followed relevant law, policy, rules, and regulations,” the report said.
“We found, however, that a $12,375 chartered flight he took in June 2017 after speaking at the developmental camp for the Golden Knights, a professional hockey team based in Las Vegas, Nevada, could have been avoided,” it added.
The National Hockey League team is owned by Bill Foley, a donor to Zinke’s congressional campaigns. The Interior Department has said Zinke’s speech did not violate any laws, rules or regulations.
Zinke has defended his use of noncommercial aircraft as necessary for reaching the remote parts of the country that his department oversees.
He has also taken heat for other spending, including the repair of a door in his office that cost nearly $140,000.
Other Cabinet members have also been scrutinized.
The U.S. Government Accountability office on Monday said the Environmental Protection Agency violated spending laws when it installed a $43,000 soundproof booth for agency Administrator Scott Pruitt.
Writing by Richard Valdmanis; editing by Jonathan Oatis